Ratchet wrenches and tools of the type in which the present invention finds utility have been long established in the relevant art. Many and varied types of ratchet and drive reversing mechanisms have been described in the literature, and some of these mechanisms have been adopted in commercial products sold for use by mechanics. The prior art structures each invoke substantially the same mechanical principles, and in each case, rotational force impressed upon a lever arm or wrench handle exerts rotational force on a tool element or workpiece, the applied rotational force coinciding with the axis of rotation of the tool handle. In each such tool, rotation of the handle in one direction will cause positive engagement of driving and driven ratchet teeth which interlock within the tool head. In such ratcheting devices, counter-rotation of the tool handle effects disengagement of the ratchet teeth to permit the drive handle to be shifted in the opposite direction for subsequent forward reactivation and drive.
A principal area of investigation and of distinction between the various ratchet tools of the prior art is the configuration of an indexing element or toothed pawl and the manner in which it is caused to shift, pivot or slide for enabling reversal of the drive direction of the tool element supported by the ratchet tool. Typically, the pawl is caused to shift between two opposed positions in which the toothed ends of the pawl engage, sequentially, at annularly spaced positions within an encircling toothed driving ring or collar of the tool head, each such shift being correlated with either clockwise or counterclockwise torque-transmitting engagement between the driving ring or collar and a driven, coaxial body or core coupled to the collar. Conveniently, the core carries shank or boss means for securement of a tool element thereto.
While many of the prior art ratchet wrenches and related tools are generally suitable for their intended uses, such tools do exhibit certain shortcomings. For example, in ratchet drive structures of the compact type and utilizing "round head" drive rings or collars, it has not heretofore been found feasible to reverse the direction of drive while retaining the wrench in its functional position on a workpiece or tool element to be driven. Rather, it has been necessary either to bring one's other hand into use to rotate a pawl-shifting mechanism so as to reverse the direction of drive, or alternatively, it has been necessary to disengage the tool from the tool element to effect the required or desired reversal of the driving mechanism. It is to the solution of this and related problems that the present invention is directed.